A number of modifications and variations of UV-light based polymerization processes are known in which adhesive compositions are coated onto a web and then polymerized using UV irradiation (See, for example, U.S. Pat. Nos. 4,415,615 and 4,513,039). Such polymerizations are normally carried out using an inert atmosphere that can be achieved either by using an oxygen free atmosphere (See, for example, Japanese Kokai No HEI 5-5014) or by using a cover sheet that excludes oxygen.
Alternatively, an adhesive can be prepared by coating the polymerization mixture onto a web and polymerizing via UV irradiation, wherein the polymerization step is carried out while the coated web is immersed in water. (See, for example, Japanese Kokai No. HEI 4-41576). When the coated web is immersed no polymerization obstruction by oxygen is said to occur.
In view of the foregoing discussed limitations of conventional on-web polymerization processes, improvements are continuously desired and sought by those within the industry. It was against this background that an improved polymerization process for producing adhesives and, in particular, acrylic-based adhesives and tapes, was sought.